应变率成像评价胸部放疗剂量与心脏损害的关系

Strain rate imaging in assessment of the relationship between the dose of thoracic radiotherapy and the radiotherapy-induced myocardial damage

目的探讨胸部放疗剂量与心脏损害的关系以及应变率成像技术(SRI)在评价胸部放疗后心脏损伤方面的临床应用价值。方法40例胸部放疗患者按照放疗进程分为5组:A组,放疗前1～2天;B组,放疗3周、累积剂量30Gy;C组,放疗4周、累积剂量40Gy;D组放疗5周、累积剂量50Gy;E组放疗6周、累积剂量60Gy;比较5个组常规超声心动图测值以及侧壁、前壁、下壁、后壁、后间隔和前间隔的基底段及中间段心内膜下心肌12个位点的收缩期最大应变率(s)、舒张早期最大应变率(e)、房缩期应变率(a)。结果B、C、D、E组前间隔、前壁、后壁的s、e均较A组明显减低,D、E组与A组相比,差异有显著统计学意义(P均<0.01),B、C组与A组相比,差异无统计学意义(P>0.05);前间隔、前壁、后壁的s、e在B、C、D、E组间差异无统计学意义(P>0.05)。左室侧壁、下壁及后间隔的s、e在各组间差异无统计学意义(P>0.05);D、E组的E/A较A组低,差异有显著统计学意义(P<0.01);B、C组的E/A较A组略低,差异无统计学意义(P>0.05)。结论胸部放疗剂量≥50Gy开始出现心脏损害的表现,SRI能较早、较敏感地评价胸部放疗后心功能的损害。

Objective To investigate the value of strain rate imaging （SRI） in detecting the relationship between the dose of thoracic radiotherapy and the radiotherapy-induced myocardial damage, and to assess the clinical value of SRI. Methods According to the process of radiotherapy, 40 patients were divided into 5 groups： group A： 1-2 d before the radiotherapy; group B： treated for 3 weeks and accumulated dose was 30 Gy; group C： treated for 4 weeks and accumulated dose was 40 Gy; group D： treated for 5 weeks and accumulated dose was 50 Gy; group E： treated for 6 weeks and accumulated dose was 60 Gy. Data measured with echocardiography and systolic strain rate （s）, early diastolic strain rate （e） and later diastolic strain rate （a） of bilateral wall, anterior wall, inferior wall, posterior wall, posterior septum and anterior septum were compared. Results The s, e of anterior septum, anterior wall and posterior wall in group B, C, D and E were obviously lower than those in group A, but compared with group A, group D and E had significantly statistical difference （both P〈 0. 01） and group B, C had no significant difference （P〉0. 05）. The s, e of anterior wall, anterior septum and posterior wall in B, C, D, E groups had no statistical difference （P〉0.05）, while the s, e of inferior wall, posterior septum, lateral wall in all groups had no statistical difference （P〉0. 05）. Left ventricular diastolic function （E/A） of group D and E was significantly lower than that in group A （P〈0. 01）. There was no statistical difference of E/A between group B, C and group A （P〉0. 05）. Conclusion Radiotherapy-induced myocardial damage appears when the dose of thoracic radiotherapy ≥50 Gy. SRI can quantitatively detect myocardial damage in patients with thoracic radiotherapy earlier.